SAN

• Company: LucasArts

SAN stands for Smush Animation Format. It is a full motion video format used in a number of different LucasArts games. What follows are some random notes based on examining files as well as older versions of the ScummVM application.

File Format

• a chunked multimedia format possibly with several variations
• multi-byte numbers are little endian (always?)
• no: the chunk lengths are big endian
• chunks are marked by FOURCCs; known FOURCCs:
  • ANIM
  • AHDR
  • FRME
  • NPAL
  • FOBJ
  • PSAD
  • TRES
  • XPAL
  • LACT
  • STOR
  • FTCH
  • SKIP
  • STRK
  • SMRK
  • SHDR
  • SDAT
  • SAUD
  • iMUS
  • FRMT
  • TEXT
  • REGN
  • STOP
  • MAP_
  • DATA
  • ETRS
• carries a payload comprised of different chunk types
• these chunk types are known:
  • codec 1
  • codec 37
  • codec 44
  • codec 47

Codec 1: RLE Encoding

• for each line in image height:
  • 16-bit number indicates encoded line size
  • while there are still encoded data bytes for this line:
    • next byte is code
    • length = code / 2 + 1
    • if bit 0 of code is set:
      • value = next byte
      • if value is 0:
        • skip (length) pixels in output
      • else:
        • put (value) in output (length) times
    • else:
      • for each count in length:
        • value = next byte
        • if value is 0:
          • skip pixel in output
        • else:
          • put value in output

Codec 37

• assign width and height
• assign bw as block width
• assign bh as block height
• codec must operate on 4x4 blocks
• assign pitch as block width * 4 (not the same as width necessarily since block width is rounded up to nearest multiple of 4)
• assign chunk size as size of input chunk - 14
• allocate a buffer with that size
• read chunk_size bytes into new buffer
• sequence number LE_16 @ chunk[2]
• decoded size is LE_32 @ chunk[4]
• maskflags = chunk[12]
• make table with pitch and chunk_buffer[1] as index:
  • index *= 255
  • if (index + 254 < sizeof(table) / 2)
    • assert error condition
  • for i = 0..255
    • j = (i + index) * 2
    • offsettable[i] = maketable_bytes[j+1] * pitch + maketable_bytes[j]
• if (chunk[0] == 0)
• else if (chunk[0] == 1)
  • "missing opcode codec47" (?)
• else if (chunk[0] == 2)
  • ...
• else if (chunk[0] == 3)
  • ...
• else if (chunk[0] == 4)
  • ...

Codec 44

• iterate through the encoded chunk from 0 to size - 14 (?):
  • size of encoded line = next LE_16 in chunk
  • while size is not 0:
    • count = next byte
    • pixel = next byte
    • put (pixel) in output (count) times
    • if size of line is not 0 at this point:
      • count = next LE_16 + 1
      • copy (count) pixels from encoded stream to output
  • at the end of line, output buffer rewinds by one pixel (?)

Codec 47

• chunk size = size of chunk passed in minus 14 bytes
• sequence number = first LE_16 of chunk
• encoded graphic data begins at chunk + 26
• the bytes at chunk[12] and chunk[13] serve as initializers for deltabufs[0] and [1] respectively

Games That Use SAN Files And Codecs They Use

• Rebel Assault
• Rebel Assualt II
• Rebel Assault II demo (video codec 37)
• Full Throttle (video codec 37)
• The Dig (video codec 37)
• The Curse Of Monkey Island (video codec 47)
• Outlaws
• Outlaws demo (video codec 47)
• Grim Fandango demo (video codec 47)
• Grim Fandango (video codec blocky16, audio codec VIMA)
• X-Wing Alliance
• Shadows of the Empire (PC)
• Star Wars Racer
• Star Wars DroidWorks
• Indiana Jones and the Infernal Machine
• Jedi Knight: Mysteries of the Sith
• Mortimer and the Riddles of the Medallion
• Making Magic CDROM (not a game but still uses smush)
• Escape From Monkey Island apparently has Smush headers but uses bink